Wireless communication networks are increasingly popular and widely deployed. Conventionally, however, wireless communication allows a single transmission at a given frequency at the same time. Thus, frequency/time division duplexing is used to allow multiple users to transmit information in a wireless communication network. However, this leads to a reduced data rate for a given channel bandwidth.
Multiple-input multiple-output (MIMO) technology is a promising candidate for next-generation wireless communications. In order to achieve a high data rate over MIMO channels, space-time codes, which perform coding across both spatial and temporal dimensions, can be utilized to maximize possible diversity and coding advantages without sacrificing channel bandwidth. However, channel state information (CSI) is not required in space-time code design.
In traditional frequency/time division duplex systems where CSI can be fed back/estimated, CSI can actually be exploited for optimum or quasi-optimum precoder and equalizer designs with the purpose of maximizing system performance. Nonetheless, since CSI is not required in space-time codes, often only limited CSI information can be available and/or the CSI can be outdated due to feedback delay. Consequently, CSI is traditionally not exploited to optimize precoder or equalizer designs in space-time coded MIMO channels.
The above-described deficiencies of wireless network communications are merely intended to provide an overview of some of the problems of today's wireless networks, and are not intended to be exhaustive. Other problems with the state of the art may become further apparent upon review of the description of various non-limiting embodiments that follows.